Heat the oil in a pan, sauté the onion and garlic, add the rice and sauté until translucent, stirring constantly. Gradually add the bouillon to the rice, stirring frequently, so that the rice is always just covered with liquid. Simmer for approx. 20 mins. until the rice is creamy and al dente. Stir in the cheese, lemon zest and juice.
Melt the butter in a wide-bottomed frying pan. Add the sugar and simmer, swirling the pan occasionally until a light brown caramel has formed. Place the tomatoes (cut side down) in the buttery caramel, cook briefly, add the lemon juice and nuts, season. Cook for approx. 2 mins. over a medium heat, turning the cherry tomatoes once.